Samuel walkee



UNITED STATES PATENT ()FFIcE.

SAMUEL WALKER, OF BIRMINGHAM, ENGLAND.

TREATING MOLTEN COPPER FOR MAKING CAST HOLLOW CYLINDERS AND OTHER CASTINGS.

SPECIFICATION formingpart of Letters Patent No. 230,369, dated July 20,1880.

Application filed April15, 1880. (No specimens.) Patented in EnglandDecember 2,1879.

To all whom it may concern:

Be it known that I, SAMUEL WALKER, a subject of the Queen of GreatBritain, residing at Birmingham, in the county of Warwick, England,(manufacturer,) have invented certain new and useful Improvements inTreating Molten Copper for Making Cast Hollow Cylinders and otherCastings, (for which I have received Letters Patent in England, No.4,926, dated December 2, 1879;) and I do hereby declare that thefollowing is a full, clear, and exact description of the invention,which will enable others skilled in the art to which it appertains tomake and use the same.

My invention has reference principally to the manufacture of the casthollow cylinders of copper from which copper tubes are made,

but is also applicable to the production of other castings ofcopper-such, for example, as copper rollers used for printing fabrics.

I will describe myinvention in connection with a cast hollow cylinder ofcopper.

In the ordinary method of casting hollow cylinders of copper the castingproduced is porous or unsound. In order to prevent porosity orunsoundness in the casting I add to the melted copper, a short timebefore pouring it in to the mold, cryolite, preferably crushed orpowdered, or any compound, natural or artificial, having a similarcomposition-such, for example, as fluor-spar or artificial fluor-' spar.v

In pouring the copper into the mold the fused cryolite may be pouredwith it. This, however, is not necessary, and in cases where it is forany reason inconvenient or undesirable to pour the fused cryolite intothe mold it may be retained in the melting-pot and the fused copper onlybe poured into the mold.

By the action of the said cryolite on the melted copper a soundcasting-that is, a casting free from the porosity of an ordinary coppercasting-is produced. The copper casting so obtained is, however, harderor less ductile than is desirable for the manufacture of tubes. In orderto correct this hardness or want of ductility, I add to the meltedcopper, in addition to the cryolite, acetate of lead, which gives therequired ductility to the copper. v

The mineral cryolite is a double fluoride of aluminium and sodium, andis an article of commerce.

I find in practice that somewhat less than one part, by weight, ofcryolite to one hundred parts, by weight, of copper and a quantity ofacetate of lead equal to about onethird the quantity of cryolite producesatisfactory results-that is, to every one hundred pounds of copperI addabout one pound of cryolite and one-quarter of a pound of acetate oflead. To these materials about one pound of borax may be added. Theproportions of the ingredients may, however, be varied.

After the copper has been melted I add the mixture of cryolite andacetate of lead either with or without borax. After from ten minutes toa quarter of an hour, or soon after the mixture of cryolite, acetate oflead, and borax has thoroughly melted, I pour into the mold the meltedcopper.

Copper castings made according to my invention may be used for a varietyof purposes to which copper cast in the ordinary way cannot be applied.

Where only freedom from porosity is required in the casting the cryolitealone may be used.

Where, in addition to freedom from porosity, ductility is required,acetate of lead may be used in addition to the cryolite.

Having now described the nature of my invention, and the manner in whichthe same is to be performed, I wish it to be understood that I claim asmy invention 1. The method of preventing porosity in cast hollowcylinders of copper and other castings of copper by adding to the meltedcopper, before pouring it into the mold, cryolite or other compound,natural or artificial, of similar composition, either alone or with theaddition of borax, substantially as hereinbefore described.

2. The method of preventing porosity in cast hollow cylinders of copperand other castings of copper, and at the same time giving ductility tothe said cast hollow cylinders and other castings of copper by adding tothe melted copper, before pouring it into the mold, cryolite or othercompound, natural or artificial, having a similar composition, togetherwith acetate of lead, either with or without the addition of borax,substantially as hereinbefore described.

SAMUEL WALKER. [L. s.] Witnesses:

RICHARD SKERRE'IT, HENRY SKERRETT, Both of N 0. 37 Temple Street,Birmingham,

